Communication standards concerning mobile communications include the third generation mobile phone (3G) standard and the LTE (Long Term Evolution) standard. Various available frequency bands are set for each communication standard and specifications for each frequency band are defined precisely.
Conventionally, a relay apparatus is used to improve coverage when a terminal device is used indoors. Any one of a plurality of frequency bandwidths defined for the communication standards is selected for access radio, which is radio communication between the relay apparatus and the terminal device, and for backhaul radio, which is radio communication between the relay apparatus and a donor base station.
Various techniques that deal with such a relay apparatus are proposed. For example, PTL 1 discloses a technique that performs beamforming of transmission of a signal relating to the backhaul radio by using a plurality of antennas provided on a relay apparatus.